textproduct: Quad Cities

KEY MESSAGES

- Chance of scattered showers and isolated storms east of Mississippi River prior to sunrise today.

- Dry and warm for most on Memorial Day. There is now a slight chance of showers in northeast IA Monday morning.

- Above normal temperatures likely for the rest of May, with highs in the 80s each day.

- Rain chances return middle of work week, with highest probabilities (50-60%) south of I-80 on Wednesday.

SHORT TERM /THROUGH TONIGHT/

Issued at 159 AM CDT Sun May 24 2026

Early morning water vapor imagery shows a shortwave trough over southwest IA and northwest MO, with a large area of high clouds over the forecast area lifting northeast. This has kept temperatures rather mild overnight, with 1 am readings largely in the mid to upper 60s. At the same time, a lake breeze boundary off Lake Michigan has moved southwest just to our east where temps were in the upper 50s/low 60s. A few scattered showers with a few isolated CGs were seen just southeast of the Quad Cities near Galesburg. These were occurring along an 850-925mb moisture gradient/boundary with 0-3km lapse rates around 6C/km and 0-3km MLCAPE values near 100 J/Kg per SPC mesoanalysis supporting the isolated lightning flashes.

Scattered showers/isolated storms will be possible prior to sunrise east of the MS RVR. No severe weather is expected, with just lightning and heavy downpours the primary hazards. Latest CAMs all show this activity increasing in coverage just to our east after 12z today. Otherwise, a rather pleasant late Spring day is in store with mostly sunny skies and temperatures topping out in the lower 80s. Forecast soundings suggest deep mixing up to 750mb may occur in our west this afternoon, which may boost temps a few degrees warmer.

Tonight...an upstream compact shortwave to dive southeast out of the northern Great Plains leading to at least an increase in clouds. A strengthening LLJ combined with steep mid level lapse rates and 30kts deep layer shear should provide enough lift for scattered showers and storms to develop over northern IA and track near our northwest counties Monday morning. Because of this, I have introduced slight chance/chance PoPs (20-40%) northwest of a Marengo to Dubuque line. Tall skinny CAPE profiles to keep severe threat very low, but an elevated hailer can't be completely ruled out.

LONG TERM /MONDAY THROUGH SATURDAY/

Issued at 159 AM CDT Sun May 24 2026

Memorial Day...the aforementioned shortwave to track across northeast IA with just enough lift albeit weakening to support isolated showers through midday north of Hwy 30. All areas will have a dry forecast during the afternoon/evening hours for any outdoor activities. Highs to top out in the mid to upper 80s.

Tuesday-Wednesday...not much change to the forecast has occurred with the newest 00z model guidance. A pseudo Rex block is expected to break down as a weak upper low over the southern Plains lifts northward in response to a building 582 dam ridge (2.5 sigma) near the US-Canada border. It appears that the best chances of rain will be centered on Wednesday, with the highest PoPs (55-60%) along and south of Hwy 34. Latest NBM 72-hr QPF probs for >0.25" has shifted slightly further south and in the 40-60% range along and south of I-80. Further shifts can be expected in later forecasts, but current thinking is that the highest amounts will occur in southeast IA, northeast MO, and west central IL. Regarding temperatures, the NBM continues to be on the higher end of all guidance with widespread highs in the mid to upper 80s. This may be too warm especially on Wednesday given opaque cloud cover, rain chances, and an easterly low level flow.

Wednesday night onward...another weak closed low or open wave over northern TX will lift north over the central Plains. This will bring increasing cloud cover through the end of the work week and slight chance/chance PoPs (20-35%) for scattered showers/storms during the afternoon hours Thursday and Friday. Once this system eventually dissipates, an Omega block will set up over the northern CONUS Friday night, leading to another dry period over the weekend and continued above normal temperatures.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1150 PM CDT Sat May 23 2026

VFR conditions to prevail through the period.

An upper level shortwave will swing east over northern MO early Sunday, with an elevated boundary just to the east of MS RVR keeping bulk of shower/storm activity to the east over IL. Latest guidance now has even lower probabilities for MVFR fog prior to 13z and have left out any mention due to expected high clouds and 3+ degree dewpoint depressions. Quiet and dry conditions are expected today as high pressure to builds into the region with just some developing Cu around 6kft late this morning/ afternoon. Winds to be predominantly under 10kts today, however RAP soundings suggest a few occasional gusts may occur at CID/DBQ this afternoon.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.